I could have sworn I saw that issue reported earlier. I thought it appeared in this thread:
http://www.asusrog.com/forums/showthread.php?5396-Magnetic-sensor-switch-issue-on-Asus-G53SW-XN1-whe..., but I can't find it. It could've been in the Notebook Review Forum. I wonder if the magnetic switch has any bearing on this behavior?
Did you check how the system's lid power settings were configured in "Control Panel-Power Options" and even drill down into Advanced Power Settings to see if they matched those of Power4Gear?
If you uninstall P4G, does that resolve the issue?
Are you sure it is going to sleep and not actually overheating and shutting down. The high fan speeds before shutdown make me suspicious of overheating. You should be able to determine this by logging temperatures or looking in the System Event Log.
It's like shark behavior. When you turn them upside down, they go into a sleep-like state. Unlike my dog - when I turn her upside down, she attacks!
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT